Homelessness of special populations is increasing at an alarming rate. Researchers have found that 30-40 percent of homeless persons alcohol problems and that at least 10-20 percent have a problem with other drugs such as crack/cocaine and heroin. The Southern Arizona Alcohol/Drug Program for the Homeless addresses the issues of homelessness and alcohol/drug abuse. The long-term objective of the program is to contribute scientific knowledge regarding effective interventions for homeless persons with alcohol/drug problems. The specific aims of the program are to assist homeless individuals who exhibit alcohol/drug problems in 1) reducing their consumption of alcohol/drugs, 2) increasing their levels of shelter and residential stability, 3) enhancement of the economic and/or employment status and 4) improvement in their health and mental health status. The program also proposes to increase cooperation and linkages among social service agencies in addressing the multiple needs of homeless individuals with alcohol/drug problems. The methods for achieving the program's objectives and specific aims involve random assignment of participants to one of two treatment groups: 1) outpatient, 2) a modified residential therapeutic community. A control group will also be followed so that the interventions can be compared with the control, i.e., services already provided by the community in exclusions of the interventions provided by this project. Process and outcome evaluations will be conducted. The process evaluation will describe the implementation and coordination of the program from its onset and examine the process as it affects the persons enrolled, those providing the intervention and the larger community of service providers. Outcomes under study include residential, economic, substance use and health status of homeless persons. A convenience sample of 432 adult male and female homeless persons will complete the interventions during the 3 years of the study. A control group of 144 will also be involved in the study over the 3 year period. The outcome evaluation will 1) examine the effects of each intervention over time using a descriptive, repeated measures design, 2) test for the similarities and differences between the two interventions using a quasi-experimental design and 3) test for similarities and differences between the two interventions and the control group.